Elon Musk’s SpaceX: here’s what caused the Starship booster explosion

The blast led to the launch pad in Boca Chica, Texas, being temporarily shut down

A booster rocket built to launch Elon Musk’s Starship spacecraft was lit in flames from an unplanned explosion during a ground test at Starbase in Boca Chica, Texas. Photo: NASASpaceflight.com

Mr Musk said the issue was caused by an engine spin start used to test all the 33 powerful Raptor engines on the rocket at once. Photo: NASASpaceflight.com

The SpaceX billionaire said on Twitter that his team was assessing the damage and that the launch pad was temporarily closed for safety. Photo: NASASpaceflight.com

SpaceX is building Starship for deep space flights, including uncrewed and crewed missions to the Moon, Mars and beyond. Photo: NASASpaceflight.com

The Raptor engines on the Super Heavy booster. Photo: SpaceX

A Starship prototype, Ship 24, was transported to the launch pad for an orbital test flight. Photo: SpaceX

SpaceX has yet to receive a launch licence before the orbital test flight of Ship 24 can take place. Photo: SpaceX

Ship 24 on the way to the launch pad in Starbase, Elon Musk's site in Boca Chica, Texas. Photo: SpaceX

A booster rocket built to launch Elon Musk’s Starship spacecraft went up in flames after an explosion during a ground test on Monday.

The SpaceX billionaire said on Twitter that his team was assessing the damage and that the launch pad at Starbase, Boca Chica, Texas, was temporarily closed for safety reasons.

Depending on the damage, the highly anticipated orbital test flight of the Starship system could be delayed. Mr Musk had hoped it would take place this month.

A fireball at the base of Booster 7 was caught on camera by news website NASASpaceflight.com.

Mr Musk said the issue was caused by a spin start test on all 33 of the rocket's powerful Raptor engines at once.

“Cryogenic fuel is an added challenge, as it evaporates to create fuel-air explosion risk in a partially oxygen atmosphere like Earth,” Mr Musk tweeted.

“That said, we have a lot of sensors to detect this.

“This particular issue, however, was specific to the engine spin start test (Raptor has a complex start sequence). Going forward, we won’t do a spin start test with all 33 engines at once.”

He said he visited the site late on Monday.

SpaceX is building Starship for deep-space flights, including uncrewed and crewed missions to the Moon, Mars and beyond.

The system is fully reusable and includes a first-stage booster called Super Heavy and an upper-stage spacecraft called Starship

A prototype of Starship was moved to its launch pad last week in preparation for an orbital test flight.

The system has been in development for many years and has finished high-altitude tests, but it has not yet completed an orbital flight.

Before the test flight can go ahead, SpaceX must obtain a launch licence from the Federal Aviation Administration in the US.

The company also has to meet 75 conditions set by the organisation to continue its work at Starbase.